Police were called to Richmond School and Sixth Form this morning after a disturbance involving students.
The disturbance occurred as pupils held a protest about access to toilets.
During the protest, at least one fire extinguisher was let off in the school grounds.
It is claimed a tree got set on fire, at least one teacher was pushed over and a window got smashed, although these reports have not been confirmed.
Videos being shared on social media show more than a dozen pupils involved in the protest and an extinguisher being activated by a male pupil.
Richmondshire Today understands the protest was planned by students after the school moved to lock the toilets during lesson time and for a period over break time.
It is claimed a petition was initially proposed but then students decided to go to the lunch hall and refuse to go to lessons.
Some students then left the hall and went outside, which is when the fire extinguisher was taken and set off.
Pupils have told their parents that 20 students have been permanently excluded due to the disturbance.
One student said: “Some people protesting about the fact that all the toilets have been closed.
“Some people set off fire extinguishers and now we’re not allowed out for break. Class has been extended.
“A bunch of pupils have been rounded up by police outside.”
Jenna Potter, headteacher at Richmond School and Sixth Form College, said in a statement to Richmondshire Today: “A small group of students has protested against the use of toilets during lesson time.
“Richmond School and Sixth Form College is proud of promoting the highest standards of behaviour and this unacceptable approach is extremely disappointing.
“The overwhelming majority of students were equally shocked at the behaviour of a small minority. Students have already been consulted and will continue to contribute to a solution.”
Nort Yorkshire Police said in a statement: “Police were contacted at 9.40am this morning to reports of criminal damage taking place at Richmond School.
“Local neighbourhood officers who were in the area attended, along with local Police Community Support Officers to provide reassurance.
“They established no criminal activity had taken place and the matter has been left with the school to deal with.”